2781421 has 4 divisors (see below), whose sum is σ = 2945052. Its totient is φ = 2617792.

The previous prime is 2781397. The next prime is 2781433. The reversal of 2781421 is 1241872.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1946025 + 835396 = 1395^2 + 914^2 .

It is a cyclic number.

It is not a de Polignac number, because 2781421 - 2⁷ = 2781293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2781451) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 81790 + ... + 81823.

It is an arithmetic number, because the mean of its divisors is an integer number (736263).

2^2781421 is an apocalyptic number.

It is an amenable number.

2781421 is a deficient number, since it is larger than the sum of its proper divisors (163631).

2781421 is a wasteful number, since it uses less digits than its factorization.

2781421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163630.

The product of its digits is 896, while the sum is 25.

The square root of 2781421 is about 1667.7592751953. The cubic root of 2781421 is about 140.6335402879.

The spelling of 2781421 in words is "two million, seven hundred eighty-one thousand, four hundred twenty-one".